Chilbolton Facility for Atmospheric and Radio Research (CFARR): Gas analyser and Sonic anemometer data

A sonic anemometer and a gas analyser measuring water vapour and carbon dioxide are co-located within a compound dedicated to measuring fluxes using the eddy covariance method at Chilbolton Observatory. The eddy covariance technique is an atmospheric measurement method used to calculate vertical turbulent fluxes within the atmospheric boundary layer. This is the lowest region of the troposphere and is usually well mixed, particularly during daylight hours, due to convective heating from the sun. It is this motion in the lower troposphere that makes the technique possible.

In order to properly measure the turbulent properties of the atmosphere the measurements must be made at a high frequency - 20 Hz for the Chilbolton Observatory system.

A sonic anemometer measures the 3 orthogonal components of the wind velocity by measuring the changes in the time of flight of sonic pulses between 3 transmitter/receiver pairs as a result of the air velocity.

A gas analyser measures the absorptance of radiation along a fixed path and uses this to determine the concentration of a gas in air. For each gas the absorptance at 2 wavelengths is measured 152 times per second, one affected by that gas and the other unaffected.

There are more accurate instruments available for measuring water vapour and carbon dioxide (e.g. a relative humidity sensor for water vapour) but the benefit of the gas analyser is that it has a sufficiently fast response to resolve the rapid changes in concentration as a result of turbulence.

Date (Publication): 2009-07-29T11:00:00

Date (Creation): 2009-07-29T11:00:00

Citation identifier: https://catalogue.ceda.ac.uk/uuid/3713e45f434e4e0bb5db6098dfba16e1

Citation identifier: NCAS British Atmospheric Data Centre (NCAS BADC) / 3713e45f434e4e0bb5db6098dfba16e1

Point of contact

Organisation name	Individual name	Electronic mail address	Role
Unavailable	Agnew, Judith	Unavailable	Author
NCAS British Atmospheric Data Centre (NCAS BADC)		badc@rl.ac.uk	Custodian
NCAS British Atmospheric Data Centre (NCAS BADC)		badc@rl.ac.uk	Distributor
Unavailable	Walden, Chris J.	Unavailable	Principal investigator
NCAS British Atmospheric Data Centre (NCAS BADC)		badc@rl.ac.uk	pointofContact
NCAS British Atmospheric Data Centre (NCAS BADC)		badc@rl.ac.uk	Publisher

Maintenance and update frequency: Monthly

Update scope: Dataset

Keywords

CFARR
gas analyser
anenometer

GEMET - INSPIRE themes, version 1.0

atmospheric conditions

Access constraints: Other restrictions

Other constraints: Access to these data is available to any registered CEDA user. Please Login or Register for a CEDA account to gain access.

Use constraints: Other restrictions

Other constraints: Under the following licence http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/, appropriate use of these data may fall under any use. This message is intended as guidance, always read the full licence. When using these data you must cite them correctly using the citation given on the CEDA Data Catalogue record.

Spatial representation type: Grid

Language: English

Topic category

Climatology, meteorology, atmosphere

Begin date: 2008-01-01T00:00:00

Unique resource identifier: WGS 84

Distribution format

Name	Version
Data are netCDF formatted

Distributor contact

Organisation name	Individual name	Electronic mail address	Role
NCAS British Atmospheric Data Centre (NCAS BADC)		badc@rl.ac.uk	Distributor

OnLine resource

Protocol	Linkage	Name
	https://catalogue.ceda.ac.uk/uuid/3713e45f434e4e0bb5db6098dfba16e1	CEDA Data Catalogue Page

OnLine resource

Protocol	Linkage	Name
	http://data.ceda.ac.uk/badc/chilbolton/data/gas-analyser-sonic-anemometer/	DOWNLOAD

Hierarchy level: Dataset

Conformance result

Title: Commission Regulation (EU) No 1089/2010 of 23 November 2010 implementing Directive 2007/2/EC of the European Parliament and of the Council as regards interoperability of spatial data sets and services

Date (Publication): 2010-12-08

Statement: Data are collected by the Chilbolton Facility for Atmospheric and Radio Research (CFARR) before being checked by the instrument scientist and then delivered for archiving with the data centre.